Button-hole sewing machines



y 9, 1967 N. DE ROBERTIS ETAL 3,318,271

BUTTON-HOLE SEWING MACHINES Filed April 2, 1964 3 Sheets-Sheet 1 F/GIl.

INVENTORS mm N/COLA DEROBERTIS 75 v a 74 COR/M00 DEROBERT/S y 1957 N. DE ROBERTIS ETAL 3,318,271

BUTTON-HOLE SEWING MACHINE5 Filed April 2, 1964 6 Sheets-Sheet 2 INVENTORS N/ COL A DE'ROBERT/S CORR/100 DE R085? 7' l5 y 9, 1967 N. DE ROBERTIS ETAL 3,318,271

BUTTON -HOLE SEWING MACH I NES Filed April 2, 1964 3 Sheets-Sheet 5 INVENTORS N/COLA DEROBERT/S COR/M00 DEROBERT/S United States Patent 3,318,271 BUTTON-HOLE SEWING MACHINES Nicola De Robertis and Corrado De Robertis, both of 566 E. 187th St., Bronx, N.Y. 10458 Filed Apr. 2, 1964, Ser. No. 356,811 3 Claims. (Cl. 112-65) This invention relates to button-hole sewing machines. Its broad object is to provide an improved mechanism for driving the needle and coacting loopers of a single-thread chain-stitched button-hole sewing machine to produce stronger and better-looking button holes at higher prO- duction speed than has been possible with other singlethread button-hole sewing machines or with double-thread button-hole sewing machines, and without the use of sewing hooks, bobbin cases, or bobbins.

In sewing button holes it is common practice to use a stitch bite of an adjustably predetermined length on both sides of the button hole, but to stagger or change to a double-length stitch bite during the barring movement of the goods while shifting from one side to the other at the ends of the button hole. An object of the invention is to adjust the swing of the needle-bar frame and the positions of the loopers on their shafts to provide a predetermined stitch bite that will remain the same length at the ends as well as on the sides of the button hole, thereby producing a stronger and better-looking button hole. Another object is to provide cam mechanisms for driving the needle and loopers, the shapes of the cams predetermining the movements and dwells of the needle and loopers, causing one looper to coact with the needle at one end of the stitch and the other looper to coact with the needle at the other end of the stitch. Another object is to provide a rack-and-pinion drive for the loopers, more precise and durable than the linkage heretofore used, and capable of producing button holes at extremely high speed.

Other objects are to provide an improved single-thread button-hole sewing machine capable of producing stronger and better-looking button holes in less time, saving thread, time and trouble; to provide a needle-bar-and-looper-drive mechanism for a single-thread button-hole sewing machine that is easily adjusted and serviced; and to provide a button-hole sewing machine having fewer parts and lower cost of manufacture.

These and other objects will be readily understood from the following specification in connection with the drawings in which FIG. 1 is a front view of the sewing machine, partly in section;

FIG. 2 is a partial top view partly in section;

FIG. 3 is a partial bottom view partly in section;

FIG. 4 is an isometric view of the looper drive mechanism;

FIG. 5 is an end view, partly in section, showing the coaction of the needle and loopers; and

FIGS. 6-11 schematically illustrate the operation of the loopers.

Briefly described, the invention comprises an improved single-thread button-hole sewing machine using a predetermined stitch bite not only at the sides of the button hole, but also at the ends, and having an improved mechanism for driving the needle and coacting loopers to produce neater and stronger button holes at higher productive speeds.

Referring to the drawings, drive shaft 10 is mounted in bearings 11 in frame 12 and driven by drive pulley 13. Drive shaft 10 carries sprocket 14 driving chain belt 15 which drives sprocket 16 on lower drive shaft 17, the drive ratio being one to one. It is understood that a vertical shaft with bevel gears, or other one-to-one driving means could be used.

Drive shaft 10 carries crank 20 driving connecting rod 21 and wristpin 22 on needle bar 23. Needle bar 23 is slidably supported in needle bar frame 25. Needle bar frame 25 is pivoted on studs and 31 in frame 12.

Drive shaft 10 also carries bevel pinion engaging bevel gear 41 running at half speed of pinion 40, the ratio being one to two. Bevel gear 41 is integral with or fixed to cam 42 engaging cam follower 43 on bellcrank 44 pivotally mounted on frame 12. Bellcrank 44 is operably connected to link 46 by pin 45. Link 46 is operably connected to bellcrank 48 by pin 47. Bellcrank 48 is pivoted on shoulder screw 49 on frame 12. Bellcrank 48 has a radial slot 50 to which link 34 is adjustably and operably connected by shoulder bolt 36. Link 34 is operably connected to needle bar frame 25 by pin 38.

Link 80 and the mechanism associated therewith (not shown) control the movements of the usual traveling work-holding plate and clamp by which the work is fed and positioned relative to the needle and loopers while the button hole is being sewed in a well-known manner.

Drive shaft 17 carries spur pinion engaging gear 61 running at half speed of pinion 60 and drive shafts 10 and 17, the ratio being one to two. Spur gear 61 is integral with or fixed on cam 62 and is rotatably mounted on shaft 59 fixed in frame 12. (FIGS. 3 and 4.) Cam 62 drives looper drive frame as a cam follower slidably mounted on guide rods 64 fixed in frame 12.

Connecting links 65 are attached to looper drive frame 63 by bolt 66. Links 65 are attached to rack cage 67 by screws 68. Cage 67 is fastened to rack 69 by a central screw (not shown) freely movable in a slot in guide block 79 which is fastened to frame 12 by screws 77. (Alternatively rack 69 could be fastened directly to looper drive frame 63.)

Rack 63 engages pinions 70 and 71 on looper shafts 72 and 73. Loopers 74 and 75 are adjustably fixed on shafts 72 and 73. Looper shafts 72 and 73 are operably mounted in block 79 fixed on frame 12.

In operation, before starting the machine, the position of link 34 in radial slot 50 corresponding to the desired stitch bite, is set by tightening shoulder bolt 36. Loopers 74 and 75 may be rotatably adjusted on looper shafts 72 and 73 to place them in position corresponding to the stitch bite selected.

Shafts 10 and 17 are driven by pulley 13 and a belt and motor not shown. Shaft 10, by crank 20, connecting rod 21, and wristpin 22, causes needle bar 23 and needle 28 to reciprocate one cycle per revolution of shaft 10.

Cam 43, driven at half speed of shaft 10 by bevel pinion 4i and gear 41, causes needle bar frame 25 to swing on studs 30 and 31 (by means of the connecting linkage) and to dwell in position at one end of the stitch bite while the needle is working on the goods during one revolution of shaft 10, and to dwell in position at the other end of the stitch bite while the needle is working on the goods during the next revolution of shaft 10.

Since link 80 and associated parts (which have heretofore caused the stitch-bite to double during the barring movement while shifting the work from one side to the other at the ends of the button hole) are independent of link 46 and associated stitch-bite-predetermining parts in the present invention, the stitch bite will have the same length at the ends of the button hole as on the sides thereof. The result is a stronger and better-looking button hole.

Drive shaft 17 drives cam 62 at half speed of shafts 17 and 10 by spur pinion 60 and gear 61. Cam 62 coacts with cam follower faces of looper drive frame 63, causing it to oscillate on guide rods 64 with movements and dwells in a manner predetermined by the shape of cam 62, the dwells permitting loopers 74 and 75 to be stationary while reciprocating movement of needle 28 continues. Rack 69 oscillates with looper drive frame 63, being connected thereto by links 65 and the central screw looper shafts 72 and 73, causing looper 74 to coact with needle 28 at the bottom of its stroke at one end of the stitch bite and causing looper 75 to coact with needle 28 at the bottom of its stroke at the other end of the stitch bite, the single thread being handled in a well-known chain-stitch manner as follows:

FIGS. 6-l1 inclusive illustrate the manner in which first one and then the other looper engage and disengage the thread. Since loopers 74 and 75 function similarly, the following descriptions apply to both loopers in the respectively opposite positions shown in FIGS. 6 and 9, 7 and'lO, and 8 and 11.

When needle point 28, FIGS. 6 (and 9), has risen partway from bottom of its stroke, point of looper 74 (or 75) enters the thread loop above the eye of needle 28. Thread loop slides freely to the heel of looper 74 (or 75) where it remains until needle 28 descends on the next stroke, FIGS. 7 (and 10).

Needle 28, FIGS. 7 (and 10) descends and enters thread loop which is held by looper 74 (or 75), FIGS. 7 (and 10). Needle 28 descends close to the heel of looper 74 (or 75) without touching it. The thread loop starts to slide down off looper 74 (or 75 shortly after the point of needle 28 descends below the bottom of the loop.

FIGS. 8 (and 11), needle 28 continues to descend. The thread loop slides off looper 74 (or 75 and is drawn up out of reach of the opposite looper 75 (or 74) on the succeeding stroke, thereby completing a link of the chain.

Having thus described the invention and its operation, it is evident that the objects stated have been attained in a practical way. While a specific embodiment of the invention has been shown and described, it is understood that changes may be made in the construction and in the arrangement of the various cooperating parts without departingfrom the spirit and scope of the invention as expressed in the following claims.

We claim:

1. In a single-thread chain-stitch button-hole sewing machine having a needle and a pair of loopers coacting therewith: means for reciprocating the needle; mechanism for swinging the needle laterally to produce a stitch bite of the same length at the ends of the button hole as on the sides thereof, said mechanism including a cam, a cam follower, and linkage adjustable to predetermine the length of the stitch bite; and looper-driving mechanism comprising a cam, a cam follower, a rack on said cam follower, a pair of pinions engaging said rack, and a looper shaft carrying each of said pinions, said loopers being adjustably fixed on said looper shafts, the shapes of the cams predetermining the movements and dwells of the needle and loopers respectively, causing one looper to coact with the needle at one end of the stitch and the other looper to coact with the needle at the other end of the stitch.

2. In a single-thread chain-stitch button-hole sewing machine having a needle and a pair of loopers coacting therewith: mechanism for reciprocating the needle; cam mechanism for swinging the needle laterally to produce a stitch bite of predetermined length; and looper-driving mechanism comprising a cam, a cam follower, a rack on said cam follower, a pair of pinions engaging said rack, and a looper shaft carrying each of said pinions, said loopers being adjustably fixed on said looper shafts, the shapes of the cams predetermining the movements and dwells of the needle and loopers respectively.

3. In a single-thread chain-stitch button-hole sewing machine having a needle and a pair of loopers coacting therewith: mechanism for reciprocating the needle and for swinging the needle laterally to produce an adjustably fixed stitch bite, in combination with looper-driving mechanism including a cam, a cam fol-lower, a rack on said cam follower, a pair of pinions engaging said rack, and a looper shaft carrying each of said pinions, said loopers being adjustably fixed on said looper shafts.

References Cited by the Examiner UNITED STATES PATENTS 1,309,575 7/1919 Hill. 1,864,218 6/1932 Reece 1l2157 2,411,493 11/1946 Wood l1273 2,560,100 7/1951 Ginsberg 112199 JORDAN FRANKLIN, Primary Examiner.

H. H. HUNTER, Assistant Examiner. 

1. IN A SINGLE-THREAD CHAIN-STITCH BUTTON-HOLE SEWING MACHINE HAVING A NEEDLE AND A PAIR OF LOOPERS COACTING THEREWITH: MEANS FOR RECIPROCATING THE NEEDLE; MECHANISM FOR SWINGING THE NEEDLE LATERALLY TO PRODUCE A STITCH BITE OF THE SAME LENGTH AT THE ENDS OF THE BUTTON HOLE AS ON THE SIDES THEREOF, SAID MECHANISM INCLUDING A CAM, A CAM FOLLOWER, AND LINKAGE ADJUSTABLE TO PREDETERMINE THE LENGTH OF THE STITCH BITE; AND LOOPER-DRIVING MECHANISM COMPRISING A CAM, A CAM FOLLOWER, A RACK ON SAID CAM FOLLOWER, A PAIR OF PINIONS ENGAGING SAID RACK, AND A LOOPER SHAFT CARRYING EACH OF SAID PINIONS, SAID LOOPERS BEING ADJUSTABLY FIXED ON SAID LOOPER SHAFTS, THE SHAPES OF THE CAMS PREDETERMINING THE MOVEMENTS AND DWELLS OF THE NEEDLE AND LOOPERS RESPECTIVELY, CAUSING ONE LOOPER TO COACT WITH THE NEEDLE AT ONE END OF THE STITCH AND THE INVENTION OF GEBELE AND SINGER, WHICH PATENT SHOWS OTHER LOOPER TO COACT WITH THE NEEDLE AT THE OTHER END OF THE STITCH. 